JavaFx阶段未出现

我试图使舞台出现，但似乎没有加载任何内容。编译它不会显示错误，但不会加载任何内容。感谢您的帮助！谢谢 其中重要的一点是，当ran是JavaFX时，没有加载任何内容。完全我真的不明白这个节目出了什么问题

package EventClick;


/**
 * Write a description of class databaseq here.
 *
 * @author (your name)
 * @version (a version number or a date)
 */
import EventClick.adminLogin.*;
import javafx.application.*;
import javafx.stage.*;
import javafx.scene.*;
import javafx.scene.control.*;
import javafx.scene.layout.*;
import javafx.geometry.*;
import java.util.*;
import javafx.util.Duration;
import javafx.animation.PauseTransition;

public class databaseq extends Application {
    Stage stage;
    Stage stage2;

    @Override public void start(Stage primaryStage) {
        stage = primaryStage;
        Platform.setImplicitExit(false);
        //Create Login Button
        Button loginbtn = new Button();
        loginbtn.setText("Login");
        loginbtn.setOnAction(e -> loginOn_Click());

        //Create Credentials Button
        Button credbtn = new Button();
        credbtn.setText("Credentials");
        credbtn.setOnAction(e -> credOn_Click());

        //Create Close Button
        Button closebtn = new Button();
        closebtn.setText("Quit");
        closebtn.setOnAction(e -> closeOn_Click());
        //Add buttons to a layout pane
        VBox pane = new VBox(10);
        pane.getChildren().addAll(loginbtn, credbtn, closebtn);
        pane.setAlignment(Pos.CENTER);

        //Add layout pane to a scene
        Scene scene = new Scene(pane, 250, 150);
        Scene scene2 = new Scene(pane, 250, 150);
        //Finish and show the scene

        primaryStage.setScene(scene);
        primaryStage.setTitle("Test Server");
        primaryStage.show();
    }

    public void loginOn_Click() {
       Alert a = new Alert(Alert.AlertType.CONFIRMATION,"Do you want to log in?",
                                                        ButtonType.YES, ButtonType.NO);        
        Optional<ButtonType> confirm = a.showAndWait();
        if(confirm.isPresent() && confirm.get() == ButtonType.YES) {

        }
    }
    public void credOn_Click() {
        Alert a = new Alert(Alert.AlertType.INFORMATION);
        a.setTitle("Test Server");
        a.setHeaderText("Loading Credentials...");
        a.setContentText("Entering User Login Server");

        a.showAndWait();
    }

    public void closeOn_Click() {
        Alert a = new Alert(Alert.AlertType.CONFIRMATION,"Are you sure you want to quit?",
                                                        ButtonType.YES, ButtonType.NO);
        Optional<ButtonType> confirm = a.showAndWait();
        if(confirm.isPresent() && confirm.get() == ButtonType.YES) {
            stage.close();
        }
    }
}

这就是把程序搞砸的代码。由于某些原因，同时加载两个场景会使显示混乱。

您正试图将窗格添加到两个不同的场景中。

 //Add layout pane to a scene
    Scene scene = new Scene(pane, 250, 150);
    Scene scene2 = new Scene(pane, 250, 150);